package ui

import (
	"strconv"
	"strings"

	"github.com/ying32/govcl/vcl"
	"github.com/ying32/govcl/vcl/types"
)

const (
	keyBtnSize   int32 = 96
	keyFontSize  int32 = 24
	dispFontSize int32 = 32
	gap          int32 = 10
	margin       int32 = 16
)

// showNumKeyPad 弹出触屏数字键盘,返回(输入字符串, 是否确认)。
// initial 为初始显示值;owner 通常为主窗体。
// 布局:顶部显示框 + 左侧 4×3 数字网格 + 右侧纵向整列(退格/清空) + 底部整行(取消/确认)。
func showNumKeyPad(owner vcl.IComponent, initial string) (string, bool) {
	form := vcl.NewForm(owner)
	form.SetCaption("输入数值")
	form.SetPosition(types.PoScreenCenter)
	form.SetBorderStyle(types.BsDialog)
	form.SetOnClose(func(sender vcl.IObject, action *types.TCloseAction) {
		*action = types.CaFree
	})

	// 显示框高度随字号。
	dispH := dispFontSize + 24
	// 左侧 4 列 x 3 行数字网格。
	gridCols := int32(4)
	gridRows := int32(3)
	gridW := gridCols*keyBtnSize + (gridCols-1)*gap
	gridH := gridRows*keyBtnSize + (gridRows-1)*gap
	// 右侧功能键列宽与数字键同宽,纵向整列高度与网格同高,两个按钮均分。
	sideW := keyBtnSize
	sideH := gridH
	// 底部整行按钮高度与数字键同高。
	bottomH := keyBtnSize

	formW := margin*2 + gridW + gap + sideW
	formH := margin + dispH + gap + gridH + gap + bottomH + margin
	form.SetWidth(formW)
	form.SetHeight(formH)

	// 显示框:横跨整个宽度。
	display := vcl.NewEdit(form)
	display.SetParent(form)
	display.SetLeft(margin)
	display.SetTop(margin)
	display.SetWidth(formW - margin*2)
	display.SetHeight(dispH)
	display.Font().SetSize(dispFontSize)
	display.SetText(initial)
	display.SetReadOnly(true)
	display.SetAlignment(types.TaRightJustify)

	var (
		result    string
		confirmed bool
	)

	curText := func() string {
		var s string
		display.GetTextBuf(&s, 64)
		return s
	}
	setText := func(s string) { display.SetText(s) }

	makeBtn := func(caption string, l, t, w, h int32) *vcl.TButton {
		b := vcl.NewButton(form)
		b.SetParent(form)
		b.SetLeft(l)
		b.SetTop(t)
		b.SetWidth(w)
		b.SetHeight(h)
		b.SetCaption(caption)
		b.Font().SetSize(keyFontSize)
		return b
	}

	gridTop := margin + dispH + gap
	gridLeft := margin

	// 数字键 4 列 x 3 行:
	//  [7][8][9][.]
	//  [4][5][6][0]
	//  [1][2][3][+/-]
	layout := []string{"7", "8", "9", ".", "4", "5", "6", "0", "1", "2", "3", "+/-"}
	for i, cap := range layout {
		col := int32(i % int(gridCols))
		row := int32(i / int(gridCols))
		btn := makeBtn(cap,
			gridLeft+col*(keyBtnSize+gap),
			gridTop+row*(keyBtnSize+gap),
			keyBtnSize, keyBtnSize)
		btn.SetOnClick(func(sender vcl.IObject) {
			c := vcl.AsButton(sender).Caption()
			s := curText()
			switch c {
			case "+/-":
				if strings.HasPrefix(s, "-") {
					s = s[1:]
				} else if s != "" {
					s = "-" + s
				}
			case ".":
				if !strings.Contains(s, ".") {
					if s == "" || s == "-" {
						s += "0."
					} else {
						s += "."
					}
				}
			default:
				s += c
			}
			setText(s)
		})
	}

	// 右侧纵向整列:退格 / 清空,均分高度。
	sideLeft := margin + gridW + gap
	sideBtnH := (sideH - gap) / 2 // 两按钮间留一个 gap
	sideBtns := []struct {
		cap string
		fn  func()
	}{
		{"退格", func() {
			s := curText()
			if len(s) > 0 {
				s = s[:len(s)-1]
			}
			setText(s)
		}},
		{"清空", func() { setText("") }},
	}
	for i, b := range sideBtns {
		btn := makeBtn(b.cap, sideLeft, gridTop+int32(i)*(sideBtnH+gap), sideW, sideBtnH)
		btn.SetOnClick(func(sender vcl.IObject) { b.fn() })
	}

	// 底部整行:取消 / 确认,均分宽度。
	bottomTop := gridTop + gridH + gap
	bottomW := (formW - margin*2 - gap) / 2 // 两按钮间留一个 gap
	cancel := makeBtn("取消", margin, bottomTop, bottomW, bottomH)
	cancel.SetOnClick(func(sender vcl.IObject) {
		confirmed = false
		form.Close()
	})
	ok := makeBtn("确认", margin+bottomW+gap, bottomTop, bottomW, bottomH)
	ok.Font().SetSize(keyFontSize + 4)
	ok.SetOnClick(func(sender vcl.IObject) {
		s := curText()
		if s == "" || s == "-" {
			confirmed = false
		} else if _, err := strconv.ParseFloat(s, 64); err != nil {
			vcl.ShowMessage("请输入合法数值")
			return
		} else {
			result = s
			confirmed = true
		}
		form.Close()
	})

	form.ShowModal()
	return result, confirmed
}